Usually peeps that know how to spell zoothanthellae, have a sense when water chemistry is out of whack.. And thats when those people do elaborate testings.. But if tank has been stable and mature and no alterations to water chemistry have been made in a while.. theres no reason for everyday or even every week testing..
Also i take water samples whenever i visit the lfs, just to have that little peace of mind,, and if lfs's test results dont convince me, i just play along...
until farther analises which results in debunking the lfs theories.
I rarely do testings, Im getting so good at detecting impurities in water column that all i have to do is taste it..soon i wont be surprised if i mutate into a fish..
Thus the reason why some of my test kits are past way beyond expiration date...However i always have every test kit available, just for kicks. Or in case i feel like doing some contraversial experiments which enables me to give the lfs a taste of their own medecine
(harassment). with a poquito of missinformation..